we used to run iRedMail (Pro) with MySQL but decided to change to LDAP. After plenty adjustments it is running fine now, except the above error message which appears in the log file every time a user logs in. How/where to fix that?

One other problem we experience is folder sharing doesn't work reliably. For one user it works, for the other not: How can I troubleshoot that problem? (have checked .../plugins/acl/...)

Since at setup I used the internal host name "mail.mydomain.lan" I would like to rename it to the official name "mail.mydomain.com". At which other places except the operating system do I have to change anything? Postfix? Anywhere else?

Lastly we intend to host several domains on the same server. How can I get rid of the certificate warning in RoundCube when using SSL? Is it possible with vhosts and one IP at all?

After plenty adjustments it is running fine now, except the above error message which appears in the log file every time a user logs in. How/where to fix that?

Does it occur while user login, or changing password?iRedMail stores mail accounts in "vmail.mailbox", not "xxx.users". And the Roundcube password plugin should be configured correctly to change password.

Did you upgrade Roundcube from an old version, or from scratch?

Volker wrote:

One other problem we experience is folder sharing doesn't work reliably. For one user it works, for the other not: How can I troubleshoot that problem? (have checked .../plugins/acl/...)

You have to enable debug mode in Dovecot first, then try to reproduce the same issue, monitor Dovecot log files to figure it out.

Volker wrote:

Since at setup I used the internal host name "mail.mydomain.lan" I would like to rename it to the official name "mail.mydomain.com". At which other places except the operating system do I have to change anything? Postfix? Anywhere else?

* Postfix config file /etc/postfix/main.cf* Dovecot config file /etc/dovecot/dovecot.conf.* Amavisd config file /etc/amavisd/amavisd.conf* /etc/hosts and /var/spool/postfix/etc/hosts. You can change /etc/hosts first, then simply copy it to /var/spool/postfix/etc/. They must be the same.

Volker wrote:

Lastly we intend to host several domains on the same server. How can I get rid of the certificate warning in RoundCube when using SSL? Is it possible with vhosts and one IP at all?

* Buy a SSL certificate from a trusted SSL provider.* Yes, one SSL certificate for all hosted mail domains.

1. I didn't get to fix this issue yet. The error msg is being logged when a user logs in. Where should I start searching for the problem?

Sorry, which issue?

Volker wrote:

4. ... Would it be possible to assign one free cert to each vhost, so the users could connect to their own domains?

You can do this in Dovecot-2, but not Postfix (except running multiple Postfix instances).iRedMail configures Apache/Dovecot/Postfix/MySQL/LDAP/PostgreSQL to use the same cert by default, for all mail domains.